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Review on J/ψ suppressions Raphaël Granier de Cassagnac LLR – École polytechnique / IN2P3 PHENIX & CMS experiments Santiago de Compostela 2009, February.

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Presentation on theme: "Review on J/ψ suppressions Raphaël Granier de Cassagnac LLR – École polytechnique / IN2P3 PHENIX & CMS experiments Santiago de Compostela 2009, February."— Presentation transcript:

1 Review on J/ψ suppressions Raphaël Granier de Cassagnac LLR – École polytechnique / IN2P3 PHENIX & CMS experiments Santiago de Compostela 2009, February 4 th

2 The normal introduction In 1986, Matsui & Satz predicted an “unambiguous” signature of QGP –Onset of quarkonia melting above a certain temperature / energy density threshold Example of assumed T d (but theorists still working on it): 2009, February 4th Review on J/psi suppressions - Matsui & Satz, PLB178 (1986) 416

3 Cold and hot SPS Normal nuclear absorption alone does a splendid job describing pA, SU and peripheral InIn and PbPb: – σ abs = 4.18 ± 0.35 mb Beyond is “anomalous suppression” – InIn looks like an onset 2009, February 4th Review on J/psi suppressions - J/ψ L NA60 preliminary σ abs = 4.18 ± 0.35 mb NA50, EPJ C39 (2005) 335 NA60, PRL99 (2007) ± 10% global systematics

4 Still open questions at SPS… Interplay shadowing – absorption  √s dependence of absorption? –Lourenço et al, arxiv:0901:3054. NA60, 168 GeV? –HP08? QM09? Unexplained rapidity dependence in pA? –Eur.Phys.J.C48:329, , February 4th Review on J/psi suppressions - C. Lourenzo P. Faccioli, P. Martins σ nDS (mb) σ EKS Tram & Arleo, EPJ. C 55, (2008)

5 However, J/ψ behave pretty much like the predicted golden QGP SPS What about RHIC?

6 R AuAu (y≈0 in PHENIX) ≈ R PbPb SPS) Lower rapidity R AA looks surprisingly similar, while there are obvious differences: –At a given N part, different energy densities… –Cold nuclear matter effects (x Bjorken, σ abs …) –… 2009, February 4th Review on J/psi suppressions - REDO Without forward PHENIX, PRL98 (2007) SPS from QM06

7 R AuAu (y≈1.7) < R AuAu (y≈0) in RHIC, more J/ψ suppression at forward rapidity ! While energy density should be smaller… R AA (y~1.7) R AA (y~0) 60% 2009, February 4th Review on J/psi suppressions - REDO PHENIX, PRL98 (2007) What is this further 40% suppression due to ?

8 @ RHIC, more suppression at forward rapidity! Two possible theoretical explanations… A. One hot: coalescence, regeneration B. One cold: saturation, shadowing

9 A. Hot coalescence, regeneration Large variety of approaches, all justify: –R AA (y=0) > R AA (y=1.7) –(more c quarks to recombine at y=0) As an example 2009, February 4th Review on J/psi suppressions - Latest references R. Thews et al, EPJ C43, 97 (2005) Yan, Zhuang, Xu, PRL97, (2006) A. Andronic et al., NPA789, 334 (2007) Ravagli, Rapp, PLB655, 126 (2007) Zhao, Rapp, PLB664, 253 (2008) A. Capella et al., EPJ C58, (2008)  O. Linnyk et al., NPA807, 79 (2008) (Apologies if I forgot somebody) Capella, Ferreiro, Tywoniuk et al. Fitting Cu+Cu, Au+Au, Mid and forward rapidity

10 B. Cold matter Assuming two shadowing schemes, derive a breakup cross sections from R dA (y) –σ EKS ≈ –1.4 mb –σ NDSG ≈ –1.5 mb –¡ Error is underestimated ! –(A. –Proper error on σ is > 2 mb And extrapolate to AuAu collisions  –(Also available for CuCu) –Mid and forward are correlated through shadowing scheme –If you believe this shadowing, large anomalous suppression, larger at forward rapidity. 2009, February 4th Review on J/psi suppressions - Forward rapidity Midrapidity More with E. Ferreiro PHENIX, PRC 77, (2008)

11 B. Cold matter More model independent… In a Glauber data-driven model, propagate what we know from R dA (y,centrality) –R AA (y,b) = Σ i R dA (–y,b i 1 ) x R dA (+y,b i 2 ) –No shadowing nor absorption schemes –Mid and forward are not correlated, less model dependent  larger uncertainties y≈0) Anomalous suppression, at least at forward rapidity! Anomalous suppression could be identical at midrapidity (No dCu, so no CuCu) 2009, February 4th Review on J/psi suppressions - Survival = – 22 % Survival = –38 % Forward rapidity Midrapidity RGdC, HP06 and QM06 PHENIX, PRC 77, (2008)

12 B. Recent CGC news 2008, October 8th Cold effects on heavy flavours - Gluon saturation could further suppress forward J/ψ in AuAu –First numerical estimate –Absolute amount of suppression is fitted to the AuAu data! –Waiting forward to new dAu data to fit them first –However, rapidity dependence should be ok –But it fails to reproduce peripheral data  –Anyway… Kharzeev, Levin, Nardi, Tuchin arXiv: & dN/dy  Not proven that J/ψ anomalous suppression is different at mid and forward rapidity!

13 How to disentangle these two scenarios experimentally? Two possible theoretical explanations… A. One hot: coalescence, regeneration B. One cold: saturation, shadowing 2009, February 4th Review on J/psi suppressions -

14 How to move forward experimentally? 1.Calm down? 2.Be more open? 3.Broaden interest? 4.Let it flow? 5.Get excited? 6.Get high? 7.Be upset? 8.Give up? (Better pA/dA reference) (Measure cc to constrain regen.) (in transverse momentum) (elliptically) (ψ’, χ c ) (in mass, looking at upsilons) (and search for onset) And move to the LHC? 2009, February 4th Review on J/psi suppressions - Some progress on all these points at this meeting ! RGdC, Quarkonia in hot and cold matters, Quark Matter 08

15 1. We need a better reference Already a lot more dAu data on tape (run8 ≈ 30 x run3) that should further help constraining cold matter effects 2009, February 4th Review on J/psi suppressions - RdA not available yet QM09 ?

16 2. Measuring open charm… … could constrain both – Regeneration α (N cc ) 2 – Initial state effect (shadowing…) common to J/ψ A factor of 2 difference between experiments ≈25% systematic error But binary scaling (within uncertainties…) 2009, February 4th Review on J/psi suppressions - ? ??? PHENIX, PRL98 (2007) to 20 cc pairs

17 2. Open charm vs rapidity Only pp, and very poorly known 2009, February 4th Review on J/psi suppressions - To know more about open charm, wait for silicon upgrades in Phenix and Star D. Hornback, PHENIX, QM08

18 Look at other observables 3. p T (broadening) 4. Elliptic flow

19 3. p T RHIC ? vs N part ? Widely unknown initial charm production: – Recombined R AA are poorly constrained… Instead look at p T : – Hot: Inherited p T should be lower than initial – Cold: Cronin effect should broaden initial p T Cronin goes like: AB = pp + α x L 2009, February 4th Review on J/psi suppressions - No strong dependence… Modest rise at forward rapidity Could be broadening No need for recombination here PHENIX, PRL 101, (2008) Mid rapidityForward rapidity

20 3. p T RHIC ? vs thickness ? 2009, February 4th Review on J/psi suppressions - No strong dependence… Modest rise at forward rapidity Could be broadening No need for recombination here 2.7 sigma slope Widely unknown initial charm production: –Recombined R AA are poorly constrained… Instead look at p T : –Hot: Inherited p T should be lower than initial –Cold: Cronin effect should broaden initial p T Cronin goes like: AB = pp + α x L Mid rapidityForward rapidity 1.2<|y|<2.2|y|<0.35

21 3. p T SPS ? Tested on many systems… 2009, February 4th Review on J/psi suppressions - SPS Cortese (NA60), Hard probes 08 + homemade powerpoint fits

22 3. Reaching higher p T Hot wind scenario → 0 –Screening length from AdS/CFT Several reasons for RAA to grow at high p T –Cronin effect –Bottom contribution –Leakage –(Anti)shadowing 2009, February 4th Review on J/psi suppressions - At QM08, some excitement about STAR’s high p T R CuCu (high p T ) ≈ 1

23 4. J/ψ elliptic flow in PHENIX 2009, February 4th Review on J/psi suppressions - If recombined, J/ψ should inherit the (rather large) charm quark elliptic flow. First measurement: Various levels of recombination… Will require RHIC II for a discriminating measurement C. QM08 E.T. HP08

24 4. But also J/ψ elliptic SPS Cannot be due to recombination –(≈0.05 cc pairs in In+In) Needs confirmation and understanding 2009, February 4th Review on J/psi suppressions - Eccentric In+In collisions F. HP08 MinBias Pb+Pb collisions R. QM08

25 Look at other quarkonia 5. Excited charmonia 6. Upsilons

26 5. Excited states (=feed down to J/ψ) Excited states should… A. melt if J/ψ suppression is cold effects + sequential melting B. also regenerate if J/ψ do (and maybe even more) Unfortunately only pp  Feeddown ratio ψ from ψ’ = 8.6 ± 2.5% ψ from χ c < 42% (90%CL) Beauty cross section  ψ from B = 4 + – 3 2 % 2009, February 4th Review on J/psi suppressions - M. PANIC08

27 6. Bottomonia Suffer less from cold matter – (x=0.02 to 0.1=EKS antishadowing) – can be checked with run8 d+Au Should measure (unseparated) excited states melting… 2009, February 4th Review on J/psi suppressions - Some news on on ψ’ and Upsilons in AA collisions at QM09? D. QM08 pp collisions AuAu collisions

28 What else ? 7. Look for onsets 8. Go to LHC, the uncharted territory

29 8. J/ψ at LHC ? A new story will begin ↓ More J/ψ melting ↓ Larger shadowing / saturation effects ↑ Larger recombination (maybe 200 cc pairs) If recombination prevails → golden signal If not, expect same or worse difficulties as at RHIC… 2009, February 4th Review on J/psi suppressions - Example of prediction A. Andronic et al., NPA789, 334 (2007) A. Andronic, Quark Matter 2008 That would be hot !

30 Pb/p 8. Quick look at shadowing on J/ψ 2009, February 4th Review on J/psi suppressions < y < < y < < y < -2.5 ALICE CMSCMS (emmited gluons and pT are neglected) A factor of ≈2x2 uncertainty on charm production from current shadowing knowledge

31 8. More LHC A lot of Upsilons –Y’ and Y’’ should be suppressed –Y shouldn’t (apart from 50% χ b feeddown) 2009, February 4th Review on J/psi suppressions - ≈ 3,700 (10 σ) ? Pb-Pb 0,5 nb –1 Frawley, Ullrich, Vogt, Phys Rept 462 (2008) 125 CMS

32 Anomalous conclusions Three years ago, in Santiago (Feb 10 th 2006) –“No strong conclusion” we had the RHIC preliminary Au+Au result, but the rapidity dependence of R AA was not clear yet… Today, one strong conclusion: –“J/ψ production is not (well and yet) understood at RHIC” Forward/mid rapidity difference could be due to: A.Regeneration / coalescence of cc pairs? B.Gluon shadowing / saturation? However, conservative cold matter approaches still gives significant anomalous suppression at least at forward rapidity… –The hot matter is deconfining some quarkonia More to come soon –dAu data ! Upsilon, ψ’ in AA collisions and LHC… 2009, February 4th Review on J/psi suppressions -

33 That’s all folks And the next speaker is…

34 What about ψ’ ? 2009, February 4th Review on J/psi suppressions - ψ’ are more absorbed than J/ψ ψ’ J/ψ NA50, EPJC48 (2006) 329 NA50, EPJC49 (2007) 559 ψ’/Drell-Yan σ abs = 4.2 ± 0.5 mb σ abs = 7.7 ± 0.9 mb 7.7 ± 0.9 mb ψ pA / A

35 Lourenço et al, arxiv: E866 : flat with x F if no shadowing is assumed… Even with no shadowing, little √s dependence of σ abs 2009, February 4th Review on J/psi suppressions -

36 J/ψ in pA, NA50 In pA, an unsolved rapidity dependence… EPJ… 2009, February 4th Review on J/psi suppressions - +50% +30%

37 R AuAu (run 4) = R AuAu (run 7) Forward rapidity only (for now) More bins at higher centrality Confirm the trend –R AA (y≈1.7) < R AA (y≈0) 2009, February 4th Review on J/psi suppressions -

38 R AuAu vs R Final CuCu analysis Slightly below 1 in CuCu 2009, February 4th Review on J/psi suppressions - PHENIX, arXiv: R AA (y~1.7) R AA (y~0)

39 R CuCu (STAR, high p T ) ≈ 1 2 sigma J/ψ signal in Cu+Cu STAR = PHENIX charm spectra R CuCu raising with p T 2009, February 4th Review on J/psi suppressions - * These are not phenix results yet, but could become as soon as the two experiments talk to each others  * *  * *  * * Plus loin, et avec les plots de Ralf and Co. + PHENIX ! Rapp & Zhao, arxiv:

40 Various R XY (p T ) Several (hints of) raising R AA (p T ) 1.R CP PbPb (NA50) 2.R AuAu (PHENIX) 3.R dAu (PHENIX) Several potential reasons: –Leakage effect, J/ψ escape High p T J/ψ forming beyond QGP –Cronin effect –Raising x Bj = less shadowing 0.02 to 0.05 from 0 to 9 GeV/c See discussion in → Think about it… 2009, February 4th Review on J/psi suppressions - PHENIX, arxiv: compared to Ferreiro, Fleuret, Rakotozafindrabe, arxiv:

41 2. Cold matter again ? Fitting an effective break- up cross section (depending on y) and extrapolate to CuCu and AuAu… Do you agree that we have poor handle on the cold nuclear matter effect? 2009, February 4th Review on J/psi suppressions - PHENIX, arxiv: STOP

42 7. Search for an onset? Onset curves fit the midrapidity AuAu data… – Chaudhury, nucl-th/ – Gunji et al, hep-ph/ (after CNM subtraction) But so do smooth curves ! – Nagle nucl-ex/ Density y=0 is incompatible with SPS onset – Linnyk & al, nucl-th/ No y=1.7 ? Wait for run7 analysis & CNM constraints! 2009, February 4th Review on J/psi suppressions - Gunji et al, PRC 76 (2007) A.K. Chaudhury, nucl-th/ STOP

43 Density threshold ? No ! J. Nagle, nucl-ex/ Onset curves fit the midrapidity data… –Chaudhury, nucl-th/ –Gunji et al, hep-ph/ (after CNM subtraction) So do smooth curves ! –Nagle nucl-ex/ Density y=0 is incompatible with SPS onset or larger y=1.7 –Linnyk & al, nucl-th/ , February 4th Review on J/psi suppressions -

44 RdAu(y) 2009, February 4th Review on J/psi suppressions -

45 RdAu(centrality,y) 2009, February 4th Review on J/psi suppressions -

46 From dA to RHIC b1b1 b2b2 b AA = x J/ψ = x J/ψ RGdC, hep-ph/ For a given A+A collision at b AA, Glauber provides a set of N+N collisions occurring at b i 1 and b i 2 One minimal assumption is rapidity factorization: R AA (|y|,b AA ) = Σ collisions [R dA (-y,b i 1 ) x R dA (+y,b i 2 )] / N coll Works (at least) for absorption & shadowing since production ~ pdf1 x pdf2 x exp –ρσ(L 1 +L 2 ) 2009, February 4th Review on J/psi suppressions -

47 Heavy flavor elliptic flow Also a surprise! Now, do bees fly? –Need the b/c+b in AA to properly estimate the b flow… (todo : average the 2 datasets cause they have different stat/syst balance) 2008, June 14th EM probes, heavy quarks, quarkonia -


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